Mixing devices in the field of preparing instant beverages are known. An example which may be mentioned is WO 03/068039.
Such mixing devices are required in order to mix the liquid, usually hot water, with the instant ingredient, which in the case of WO 03/068039 is an instant powder. Referring to said example WO 03/068039, such a mixing device has a mixing chamber containing a rotor. The mixing chamber is usually subdivided into an inlet chamber and a rotor chamber. At the top, the inlet chamber is provided with an access opening through which portions of instant powder are delivered to the inlet chamber. The inlet chamber furthermore has an inlet mouth by means of which the hot water is supplied. When the inlet chamber is round and the inlet is oriented radially, mixing occurs in the inlet chamber as a result of the liquid making a circular motion. From the inlet chamber, the liquid with the instant powder passes to the rotor chamber in which the rotor is located. The rotor is, as is also the case in WO 03/068039, usually arranged so that it rotates about a horizontal axis of rotation. As a result thereof, a pipe bend is usually provided between the inlet chamber and the rotor chamber. The rotor may perform various functions, optionally in combination, and may, partly for this reason, have various forms. One function is to improve the mixing. Another function is foaming up the beverage by mixing in air or by another way. Yet another function is a conveying function. Furthermore, an outlet is connected to the mixing chamber, usually to the rotor chamber near the rotor, in order to discharge the mixture produced, generally into a container, such as a beaker, mug, cup or pot, from which the beverage can be drunk or poured. The outlet is generally horizontally oriented and has a discharge part at the end having an outflow opening which is directed downwards by means of a bend.
The known mixing devices for preparing an instant beverage have various shortcomings, that is to say there are various points which can be improved upon.
A problem which occurs with mixing devices such as those known from WO 03/068039 is that encrustation, that is encrustation of instant ingredient particles, takes place in the pipe bend leading from the inlet chamber to the rotor chamber, in particular in the outer curve thereof. This encrustation results in soiling which is undesirable and has to be removed on a regular basis.
It is an object of the present invention to improve the through-flow in the pipe bend in such a manner that the deposition of particles in said pipe bend are prevented and thereby also to prevent encrustation.